Firefox in its default configuration does nothing about privacy because just the IP address and user-agent are unique enough to track you. It may actually make it even worse because Firefox' marketshare is so small that the user-agent sticks out like a sore thumb.

You need uBlock Origin to have any chance at privacy.

Firefox these days includes a number of features which threaten user's privacy that must be disabled. Their biggest sins I think were forcing Pocket onto people by default, their new tab page, searching from the address bar, and prefetch.